Active matrix electroluminescent (AMEL) display screens are very useful for head mounted and other personal display applications because of their low weight, compact size and ruggedness. Monochrome AMEL displays processed on single crystal silicon on insulator (SOI) substrates have demonstrated high-resolution with high luminescence and reliability in a compact package suitable for personal viewer display applications.
A desirable object of personal viewing devices is the provision of full color. In thin film electroluminescent (TFEL) devices there are several methods of obtaining a full color display. One such method is the use of patterned filters superimposed over a "white" screen to provide the three primary colors. An example of a TFEL screen of this type is shown in Sun, et al., U.S. Pat. No. 5,598,059.
The problem with this type of structure is that each pixel consists of three sub-pixels, each emitting red, green or blue, respectively. This adds greatly to the size and bulk of the display, requires more interconnects to the driving electronics and, accordingly, tradeoffs must be made between resolution and the size of the display. Another problem with white screen and filter architecture is that insufficient blue is provided due to the limited phosphor emission below 470 nanometers and the broad absorption edge of the filter.
The same technique can be accomplished with four active matrix pixels to produce a single color pixel, but the large die area needed for such an array adversely effects the IC process yield display cost. The energy dissipation in such a device is four times greater than an even smaller monochrome display with the same resolution using AMEL architecture.
What is needed, therefore, is a high-resolution, color, AMEL display device which can provide improved color performance, reduced power consumption and low manufacturing cost.